Comparison of extradural and intravenous diamorphine as a supplement to extradural bupivacaine

The influence of route of administration (extradural as compared with intravenous) of diamorphine 0.5 mg/hour as a supplement to extradural bupivacaine (0.125% at 15 ml/hour) was investigated in two groups of 20 patients who underwent major abdominal gynaecological surgery. Significantly more patients in the intravenous group withdrew because of inadequate analgesia (p less than 0.05). Those in the extradural group were significantly more drowsy throughout the study (p less than 0.01), but no major side effects were encountered.